The aim of this project is to develop strategies for a genetic analysis of complex and heterogeneous diseases such as juvenile periodontitis. For this study we will take pedigrees ascertained through juvenile perodontitis now available from the Division of Human Genetics of the University of Maryland and simulate phenotypes under competing models of inheritance, both genetic and non-genetic. These sumulated data will then be grouped into those supporting particular etiological mechanism, e.g. autosomal dominant, autosomal recessive, non-genetic inheritance, etc., by computing the likelihood of each mechanism on each simulated phenotypic array for a particual pedigree. Comparing the rates of misclassification among the various etiological mechanisms with these simulated data will define the feasibility of applying these techniques to analysis of etiological heterogeneity in future studies of juvenile periodontitis and other complex periodontal diseases.